The present invention relates to a method and apparatus for assuming and maintaining secure control of an aircraft in the event of an intended, attempted or actual attack upon, or incapacity of, the pilot(s) of the aircraft. As is well known, terrorists and hijackers sometimes attempt to assume control of an aircraft by intimidating either the passengers and/or the crew. Once the attacker (terrorist or hijacker) takes control of an aircraft, he or she may cause it to fly to an inappropriate destination or may even cause the aircraft to crash.
The U.S. Pat. No. 6,917,863 discloses a method and system for assuming and maintaining secure remote control of an aircraft in the event of an actual or potential aircraft hijacking or incapacity of the pilot(s) due to illness or injury. The U.S. Patent Publication No. U.S. 2006/0032978 discloses a number of scenarios which may arise, in the event of a hijacking or other incapacity of the pilot(s), which entail an early autopilot/flight management computer control phase, followed by a later remote pilot control phase, whereby personnel on the ground or in another aircraft can assist in bringing the aircraft down for a safe landing at a desired location.
While the aforementioned patent and published patent application disclose various methods of interrupting on-board pilot control of the aircraft, and operating the aircraft either automatically, with the aid of an autopilot and/or flight control system, or by a remote off-board (off-aircraft) human pilot, they do not disclose how the on-board operation of the aircraft may be disabled, and how control by either automated equipment or by a remote pilot may be maintained, in every type of aircraft. In the event of a hijacking, it is imperative that, once an emergency condition is declared, no one on board the aircraft (including the attackers) be allowed to influence or control the flight path of the aircraft.
Some aircraft are entirely electronically controlled—that is, so-called “fly-by-wire” aircraft—in which substantially all of the control devices operated manually by the on-board pilot(s)—e.g. the control yoke, control knobs, rudder pedals and engine controls—generate electronic control signals that are supplied to the various mechanical actuators that cause movement of the aircraft attitude control surfaces—e.g. the ailerons, flaps, elevator, rudder and trim tabs—and the aircraft engines—e.g. throttle control, mixture control and fuel source controls. With such fly-by-wire aircraft, pilot operation can be disabled by interrupting or preventing the transmission of the electronic control signals generated by the manually operated control devices on the flight deck.
The majority of aircraft, however, are not “fly-by-wire” and instead entail a mechanical connection between the manually operated pilot control devices on the flight deck and the mechanical actuators which cause movement of the aircraft attitude control surfaces, aircraft engine components and the like. These mechanical connections are made by a variety of means including rods, levers and cables which transmit mechanical motion from one device to another or by hydraulic or pneumatic tubes and/or hoses which transmit fluid pressure to the mechanical actuators.